1. Field of the Invention
The present invention relates to an apparatus that drills aligned dowel holes in companion workpieces such that the workpieces when mated are in accurate alignment.
2. Description of the Prior Art
Dowels are used to improve the structural strength of the connection of two companion workpieces. Dowels are typically used in articles of furniture, such as sofa frames, and in cabinetmaking. The positioning of the dowel holes in the mating surfaces of companion workpieces is crucial. If the dowel holes in the companion workpieces are not precisely aligned withe each other, a noticeable misalignment of the workpieces will result. The positioning and drilling of the dowel holes to ensure that the dowel holes drilled in companion workpieces align with each other is a time-consuming task.
Several prior art patents attempt to resolve the problem of accurately positioning dowel holes in companion workpieces.
U.S. Pat. No. 1,556,540 to Patterson, granted in October of 1925, shows a device that secures a piece of wood between horizontally spaced clamping jaws that are slidably mounted on a calibrated fence. A drilling mechanism is positioned to drill the wood held by the clamping jaws at a predetermined point. The device of the Patterson Patent provides for drilling dowel holes in wood stock where many dowel holes are drilled in a run of uniform stock. The device does not provide for quick and precise drilling of dowels in wood stock that is not part of a uniform run.
U.S. Pat. No. 2,928,441 to Farrow, granted in March of 1960, describes a dowel hole boring jig that includes a plate having a slot therein for guiding a drill. The workpiece is placed against a bar that is parallel to the drilling axis for positioning of a first dowel hole. To position a second dowel hole, a spacer is placed between the workpiece and the bar establishing a new dowel hole position. The jig of the Farrow Patent only provides for drilling dowel holes proximate an end of a workpiece.
U.S. Pat. No. 2,943,653 to Crider, granted in July of 1980, shows a structure having two clamping members which are horizontally movable with respect to each other by right and left-hand screws and hold a workpiece therebetween. A drilling mechanism is positioned on the structure such that the mechanism will drill a hole in the workpiece when the workpiece is held by the clamping members. In addition, the workpiece is also held down by a top clamp. A first dowel hole is drilled into the longitudinal end of a workpiece. To drill a matching dowel hole into the side of a companion workpiece, one of the clamping members is pivoted away and the longitudinal end of the second workpiece is placed against the other clamping member. The Crider Patent only provides for drilling alignable dowel holes in companion workpieces proximate their ends.
U.S. Pat. No. 3,708,237 to Kruse, granted in January of 1973, shows a dowel hole drilling jig that clamps the companion workpieces in an aligned side-by-side manner for drilling of the dowel holes. A drilling guide on a carriage is movable along a set of tracks which run above the workpiece surfaces transversely of their longitudinal axes. The drilling guide is positioned along the track over one workpiece and a dowel hole drilled. The guide is then moved along the tracks to the companion workpiece wherein a second dowel hole is drilled. However, the jig of the Kruse Patent is cumbersome to use since the workpieces have to be aligned with each other initially and then re-aligned if a second set of dowel holes is desired.
U.S. Pat. No. 4,174,917 to Brower, granted in November of 1979, describes a doweling device that is adaptable for use in a radial arm saw structure. A drill mechanism is exchanged for the radial arm saw and a movable platform is placed on the workbed of the saw table. The platform is movable by a screw mechanism which is turned by handles to locate the dowel holes to be drilled in a workpiece. A pair of guides for positioning the workpieces are included on the platform. The first dowel hole is drilled in the longitudinal end of a workpiece by holding the workpiece against a guide and moving the platform towards the drill. The second matching dowel hole in a companion workpiece is drilled by placing the companion workpiece transversely against a forwardly disposed surface of the guide. The device of the Brower Patent is awkward in use since the workpieces must be held by the operator while the platform is moved to drill the dowel hole.